scholarly journals Postactivation depression of the Ia EPSP in motoneurons is reduced in both the G127X SOD1 model of amyotrophic lateral sclerosis and in aged mice

2015 ◽  
Vol 114 (2) ◽  
pp. 1196-1210 ◽  
Author(s):  
A. Hedegaard ◽  
J. Lehnhoff ◽  
M. Moldovan ◽  
L. Grøndahl ◽  
N. C. Petersen ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Symptom Onset ◽  
Time Course ◽  
Monosynaptic Reflex ◽  
Spinal Motoneurons ◽  
Adult Mice ◽  
Asymptomatic Phase ◽  
Postactivation Depression ◽  
Lateral Sclerosis

Postactivation depression (PActD) of Ia afferent excitatory postsynaptic potentials (EPSPs) in spinal motoneurons results in a long-lasting depression of the stretch reflex. This phenomenon (PActD) is of clinical interest as it has been shown to be reduced in a number of spastic disorders. Using in vivo intracellular recordings of Ia EPSPs in adult mice, we demonstrate that PActD in adult (100–220 days old) C57BL/6J mice is both qualitatively and quantitatively similar to that which has been observed in larger animals with respect to both the magnitude (with ∼20% depression of EPSPs at 0.5 ms after a train of stimuli) and the time course (returning to almost normal amplitudes by 5 ms after the train). This validates the use of mouse models to study PActD. Changes in such excitatory inputs to spinal motoneurons may have important implications for hyperreflexia and/or glutamate-induced excitotoxicity in the neurodegenerative disease amyotrophic lateral sclerosis (ALS). With the use of the G127X SOD1 mutant mouse, an ALS model with a prolonged asymptomatic phase and fulminant symptom onset, we observed that PActD is significantly reduced at both presymptomatic (16% depression) and symptomatic (17.3% depression) time points compared with aged-matched controls (22.4% depression). The PActD reduction was not markedly altered by symptom onset. Comparing these PActD changes at the EPSP with the known effect of the depression on the monosynaptic reflex, we conclude that this is likely to have a much larger effect on the reflex itself (a 20–40% difference). Nevertheless, it should also be accounted that in aged (580 day old) C57BL/6J mice there was also a reduction in PActD although, aging is not usually associated with spasticity.

scholarly journals Increased axon initial segment length results in increased Na+ currents in spinal motoneurones at symptom onset in the G127X SOD1 mouse model of Amyotrophic Lateral Sclerosis

2020 ◽  
Author(s):  
H. S. Jørgensen ◽  
D.B. Jensen ◽  
K.P. Dimintiyanova ◽  
V.S. Bonnevie ◽  
A. Hedegaard ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Mouse Models ◽  
Symptom Onset ◽  
Repetitive Firing ◽  
Spinal Motoneurones ◽  
Axon Initial Segments ◽  
Sod1 Mouse ◽  
G93a Sod1 ◽  
Lateral Sclerosis

Amyotrophic lateral sclerosis is a neurodegenerative disease preferentially affecting motoneurones. Transgenic mouse models have been used to investigate the role of abnormal motoneurone excitability in this disease. Whilst an increased excitability has repeatedly been demonstrated in vitro in neonatal and embryonic preparations from SOD1 mouse models, the results from the only studies to record in vivo from spinal motoneurones in adult SOD1 models have produced conflicting findings. Deficits in repetitive firing have been reported in G93A SOD1 mice but not in presymptomatic G127X SOD1 mice despite shorter motoneurone axon initial segments (AISs) in these mice.These discrepancies may be due to the earlier disease onset and prolonged disease progression in G93A SOD1 mice with recordings potentially performed at a later sub-clinical stage of the disease in this mouse. To test this, and to explore how the evolution of excitability changes with symptom onset we performed in vivo intracellular recording and AIS labelling in G127X SOD1 mice immediately after symptom onset. No reductions in repetitive firing were observed showing that this is not a common feature across all ALS models. Immunohistochemistry for the Na+ channel Nav1.6 showed that motoneurone AISs increase in length in G127X SOD1 mice at symptom onset. Consistent with this, the rate of rise of AIS components of antidromic action potentials were significantly faster confirming that this increase in length represents an increase in AIS Na+ channels occurring at symptom onset in this model.HighightsIn vivo electrophysiological recordings were made in symptomatic G127X SOD1 mice.There were no deficits in repetitive firing in motoneurones in G127X mice.Increased persistent inward currents were still present in the symptomatic mice.Results suggest increases in Na+ currents at axon initial segments (AISs).Immunohistochemistry showed that motoneurone AISs were longer and thinner.

Age at symptom onset influences cortical thinning distribution and survival in amyotrophic lateral sclerosis

2021 ◽  
Author(s):  
Pilar M. Ferraro ◽  
Corrado Cabona ◽  
Giuseppe Meo ◽  
Claudia Rolla-Bigliani ◽  
Lucio Castellan ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Symptom Onset ◽  
Cortical Thinning ◽  
Lateral Sclerosis

scholarly journals Where and Why Modeling Amyotrophic Lateral Sclerosis

2021 ◽  
Vol 22 (8) ◽  
pp. 3977
Author(s):  
Francesco Liguori ◽  
Susanna Amadio ◽  
Cinzia Volonté
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Comparative Analysis ◽  
Clinical Presentation ◽  
In Vivo Models ◽  
Comprehensive Review ◽  
Common Features ◽  
Neuroinflammatory Disease ◽  
Multicellular Organisms ◽  
Lateral Sclerosis

Over the years, researchers have leveraged a host of different in vivo models in order to dissect amyotrophic lateral sclerosis (ALS), a neurodegenerative/neuroinflammatory disease that is heterogeneous in its clinical presentation and is multigenic, multifactorial and non-cell autonomous. These models include both vertebrates and invertebrates such as yeast, worms, flies, zebrafish, mice, rats, guinea pigs, dogs and, more recently, non-human primates. Despite their obvious differences and peculiarities, only the concurrent and comparative analysis of these various systems will allow the untangling of the causes and mechanisms of ALS for finally obtaining new efficacious therapeutics. However, harnessing these powerful organisms poses numerous challenges. In this context, we present here an updated and comprehensive review of how eukaryotic unicellular and multicellular organisms that reproduce a few of the main clinical features of the disease have helped in ALS research to dissect the pathological pathways of the disease insurgence and progression. We describe common features as well as discrepancies among these models, highlighting new insights and emerging roles for experimental organisms in ALS.

scholarly journals Cognitive dysfunction in amyotrophic lateral sclerosis: can we predict it?

2021 ◽  
Author(s):  
Fabiola De Marchi ◽  
◽  
Claudia Carrarini ◽  
Antonio De Martino ◽  
Luca Diamanti ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Time Course ◽  
Neurodegenerative Disorder ◽  
Early Stage ◽  
Multisystem Disorder ◽  
Behavioral Impairment ◽  
Behavioral Impairments ◽  
Als Patients ◽  
Disease Stages ◽  
Lateral Sclerosis

Abstract Background and aim Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder characterized by the degeneration of both upper and lower motoneurons in the brain and spinal cord leading to motor and extra-motor symptoms. Although traditionally considered a pure motor disease, recent evidences suggest that ALS is a multisystem disorder. Neuropsychological alterations, in fact, are observed in more than 50% of patients: while executive dysfunctions have been firstly identified, alterations in verbal fluency, behavior, and pragmatic and social cognition have also been described. Detecting and monitoring ALS cognitive and behavioral impairment even at early disease stages is likely to have staging and prognostic implications, and it may impact the enrollment in future clinical trials. During the last 10 years, humoral, radiological, neurophysiological, and genetic biomarkers have been reported in ALS, and some of them seem to potentially correlate to cognitive and behavioral impairment of patients. In this review, we sought to give an up-to-date state of the art of neuropsychological alterations in ALS: we will describe tests used to detect cognitive and behavioral impairment, and we will focus on promising non-invasive biomarkers to detect pre-clinical cognitive decline. Conclusions To date, the research on humoral, radiological, neurophysiological, and genetic correlates of neuropsychological alterations is at the early stage, and no conclusive longitudinal data have been published. Further and longitudinal studies on easily accessible and quantifiable biomarkers are needed to clarify the time course and the evolution of cognitive and behavioral impairments of ALS patients.

scholarly journals LanCL1 promotes motor neuron survival and extends the lifespan of amyotrophic lateral sclerosis mice

2019 ◽  
Vol 27 (4) ◽  
pp. 1369-1382 ◽  
Author(s):  
Honglin Tan ◽  
Mina Chen ◽  
Dejiang Pang ◽  
Xiaoqiang Xia ◽  
Chongyangzi Du ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Neuronal Survival ◽  
Disease Onset ◽  
Alternative Mechanism ◽  
Specific Expression ◽  
Motor Neuron Survival ◽  
Lateral Sclerosis

Abstract Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive loss of motor neurons. Improving neuronal survival in ALS remains a significant challenge. Previously, we identified Lanthionine synthetase C-like protein 1 (LanCL1) as a neuronal antioxidant defense gene, the genetic deletion of which causes apoptotic neurodegeneration in the brain. Here, we report in vivo data using the transgenic SOD1G93A mouse model of ALS indicating that CNS-specific expression of LanCL1 transgene extends lifespan, delays disease onset, decelerates symptomatic progression, and improves motor performance of SOD1G93A mice. Conversely, CNS-specific deletion of LanCL1 leads to neurodegenerative phenotypes, including motor neuron loss, neuroinflammation, and oxidative damage. Analysis reveals that LanCL1 is a positive regulator of AKT activity, and LanCL1 overexpression restores the impaired AKT activity in ALS model mice. These findings indicate that LanCL1 regulates neuronal survival through an alternative mechanism, and suggest a new therapeutic target in ALS.

scholarly journals In Vivo Validation of Bimolecular Fluorescence Complementation (BiFC) to Investigate Aggregate Formation in Amyotrophic Lateral Sclerosis (ALS)

2020 ◽  
Author(s):  
Emily K Don ◽  
Alina Maschirow ◽  
Rowan A W Radford ◽  
Natalie M Scherer ◽  
Andres Vidal-Itriago ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Disease Onset ◽  
Bimolecular Fluorescence Complementation ◽  
Aggregate Formation ◽  
Reporter Protein ◽  
Fluorescent Reporter ◽  
Lateral Sclerosis ◽  
Fluorescence Complementation ◽  
Bimolecular Fluorescence

AbstractAmyotrophic lateral sclerosis (ALS) is a form of motor neuron disease (MND) that is characterized by the progressive loss of motor neurons within the spinal cord, brainstem and motor cortex. Although ALS clinically manifests as a heterogeneous disease, with varying disease onset and survival, a unifying feature is the presence of ubiquitinated cytoplasmic protein inclusion aggregates containing TDP-43. However, the precise mechanisms linking protein inclusions and aggregation to neuronal loss are currently poorly understood.Bimolecular Fluorescence Complementation (BiFC) takes advantage the association of fluorophore fragments (non-fluorescent on their own) that are attached to an aggregation prone protein of interest. Interaction of the proteins of interest allows for the fluorescent reporter protein to fold into its native state and emit a fluorescent signal. Here, we combined the power of BiFC with the advantages of the zebrafish system to validate, optimize and visualize of the formation of ALS-linked aggregates in real time in a vertebrate model. We further provide in vivo validation of the selectivity of this technique and demonstrate reduced spontaneous self-assembly of the non-fluorescent fragments in vivo by introducing a fluorophore mutation. Additionally, we report preliminary findings on the dynamic aggregation of the ALS-linked hallmark proteins Fus and TDP-43 in their corresponding nuclear and cytoplasmic compartments using BiFC.Overall, our data demonstrates the suitability of this BiFC approach to study and characterize ALS-linked aggregate formation in vivo. Importantly, the same principle can be applied in the context of other neurodegenerative diseases and has therefore critical implications to advance our understanding of pathologies that underlie aberrant protein aggregation.

scholarly journals Inhibition of mTOR during a postnatal critical sensitive window rescues deficits in GABAergic PV cell connectivity and social behavior caused by loss of TSC1

2020 ◽  
Author(s):  
Mayukh Choudhury ◽  
Clara A. Amegandjin ◽  
Vidya Jadhav ◽  
Josianne Nunes Carriço ◽  
Ariane Quintal ◽  
...  
Keyword(s):  
Social Behavior ◽  
Time Course ◽  
Cell Types ◽  
Developmental Time ◽  
Adult Mice ◽  
Mtorc1 Signaling ◽  
Pv Cell ◽  
Mechanistic Basis

ABSTRACTMutations in regulators of the Mechanistic Target Of Rapamycin Complex 1 (mTORC1), such as Tsc1/2, lead to neurodevelopmental disorders associated with autism, intellectual disabilities and epilepsy. Whereas the effects of mTORC1 signaling dysfunction within diverse cell types are likely critical for the onset of the diverse neurological symptoms associated with mutations in mTORC1 regulators, they are not well understood. In particular, the effects of mTORC1 dys-regulation in specific types of inhibitory interneurons are unclear.Here, we showed that Tsc1 haploinsufficiency in parvalbumin (PV)-positive GABAergic interneurons either in cortical organotypic cultures or in vivo caused a premature increase in their perisomatic innervations, followed by a striking loss in adult mice. This effects were accompanied by alterations of AMPK-dependent autophagy in pre-adolescent but not adult mice. PV cell-restricted Tsc1 mutant mice showed deficits in social behavior. Treatment with the mTOR inhibitor Rapamycin restricted to the third postnatal week was sufficient to permanently rescue deficits in both PV cell innervation and social behavior in adult conditional haploinsufficient mice. All together, these findings identify a novel role of Tsc1-mTORC1 signaling in the regulation of the developmental time course and maintenance of cortical PV cell connectivity and provide a mechanistic basis for the targeted rescue of autism-related behaviors in disorders associated with deregulated mTORC1 signaling.

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